11i processor sets = PRM ???

[Arne Gogala]

I?ve just read some HP-UX 11i feature lists. There ist a feature called processor sets and it seems to be a PRM for free? Can one compare this feature with the HP PRM which I?m currently interested in for HP-UX 11.00 ?

Thanks for your help, Arne

[melvyn burnard]

PSETS is an additional functionality of PRM version C.02.00, available as of 1 September 2001.
PRM is a separately purchaseable add-on product.
The Release Notes will be available, along with existing version Release Notes at:

http://docs.hp.com/hpux/ha/index.html#Process%20Resource%20Manager

[Carsten Krege]

PRM 2.0 uses the pset API, but is not meant as a tool for full pset administration.

Processor sets (Psets) allow processors to be grouped together in a set by the system administrator. Processes, applications and users can then be assigned to these groups of processors, or processor sets. PRM allows the allocation of CPU resources to be expanded to include the concept of Psets. The default Pset initially contains all the processors in the system and is setup at system initialization time. From the PRM perspective, there are no changes required to the configuration or operation to run processes, applications or users in the default Pset. The fact that the entities are running in the default Pset is invisible to the user. However, if additional Psets are desired, the system administrator may specify that a PRM group is now a Pset PRM group. The Pset PRM group, instead of receiving shares of available CPU cycles, is now assigned a specified number of processors. Memory records may reference Pset PRM groups in the same manner in which they previously referenced traditional Fair-Share Scheduler (FSS) PRM groups. Application and User records may also refer to the new Pset PRM group.

Carsten

[Jonathan Fears]

Processor sets (psets) is a feature of the HP-UX 11i kernel. PRM simply uses the psets API to aid in resource management. Although PRM 2.0 runs on HP-UX 11.x (11.0 or 11i), HP-UX 11i must be used to utilize this kernel functionality. Earlier revisions of PRM that run on HP-UX 11i do not recognize psets, neither do revisions of PRM running on HP-UX 11.0.
A great benefit of PRM 2.0 comes in dealing with resource-intensive applications and users. There are some applications that need to be isolated in order to ensure dedicated CPU and memory cycles. Since resource management with PRM is done at the group level, these individual users and applications may not get the resources required in a group consisting of many users or applications. With revisions of PRM prior to 2.0, the remedy is to reduce the size of the group or create a group specifically for the resource-intense user or application. However, the group's CPU entitlement is still a percentage of the entire system's CPU availability. With PRM 2.0, these types of applications can be assigned to PSET PRM groups. With PSET PRM groups, the CPU entitlement is specified by assigning the group a subset of the system?s processors, instead of assigning it shares as do previous versions. No other group can use the CPUs assigned to a PSET PRM group until a new configuration is loaded. This creates an isolated area for these applications to run. This is especially good for those applications that like to assume they alone have control of the entire system. As far as they are concerned, the ?entire system? is the CPUs assigned to their PSET PRM group. At system initialization, a default pset is created that contains all of the system?s processors. The system administrator can create additional PSET PRM groups and assign processors, users, and applications to them. Only the processor with id 0 is required to remain in the default pset. The memory entitlement for a PSET PRM group is specified in shares, as are the resource entitlements (CPU, memory, disk) for traditional PRM groups, now called FSS (Fair Share Scheduler) PRM groups.